Cybersecurity Briefing — January 6, 2020

Executive briefing: CISA’s AA20-006A alert (6 January 2020) warned of potential Iranian cyber response scenarios—wipers, destructive ICS/OT actions, spearphishing, and DNS hijacking—following geopolitical tensions. This briefing operationalizes the alert with response lanes, detection content, governance cadence, and linked internal guidance.

Why it matters: The alert summarized historical Iranian tactics (password spray, credential theft, destructive malware such as Shamoon/ZeroCleare) and urged immediate validation of incident-response, logging, and segmentation. Organizations with exposed remote access, OT assets, or unmanaged DNS must execute targeted hardening.

Threat scenarios and controls

72-hour action plan

1. Day 0–1: Freeze non-essential changes; confirm MFA on externally exposed apps; lock registrars; review VPN, OWA, Citrix, and SSH exposure; enable verbose logging (DNS, VPN, IdP, EDR); capture golden images of domain controllers and OT jump servers.
2. Day 1–2: Run password-spray hunting queries; patch edge devices; rotate privileged credentials; validate offline/immutable backups; test restore of critical systems; disable legacy protocols (NTLMv1, SMBv1, older TLS).
3. Day 2–3: Conduct tabletop for destructive malware and DNS hijack; validate playbooks and comms trees; issue employee phishing warning with specific IOCs and reporting instructions; validate escalation pathways to law enforcement and sector ISACs.

Incident-routing diagram

        Alert → Triage (SOC) → Classify (Spray / Wiper / DNS) →
          - Spray: IdP risk rules → force reset & MFA check → report to CTI
          - Wiper: isolate host → backup restore → exec briefing → law enforcement as needed
          - DNS: lock registrar → revert records → notify customers → enable DNSSEC
            

Detection content (starter queries)

• Password spray: Count failed logins per IP/ASN > threshold across IdP/VPN/OWA within 15 minutes.
• DNS tamper: Compare authoritative records hourly against baseline; alert on NS/A/MX/TXT changes outside change window.
• Wiper precursors: EDR for mass file handles with overwrite patterns; PowerShell invoking cipher /w or wevtutil cl.
• OT anomalies: Modbus function codes outside allowlist; DNP3 unsolicited responses; unexpected SMB traffic in OT zones.

Metrics and governance

• MTTD/MTTR: Detect spray attempts in <5 minutes; contain destructive activity in <30 minutes from first alert.
• Coverage: 100% MFA on external apps; 100% registrar locks; ≥95% OT remote sessions through jump hosts; ≥90% backups tested quarterly.
• Hunting cadence: Daily spray hunts; weekly DNS diffs; monthly restore drills with evidence.
• Evidence: SIEM queries, backup restore logs, MFA enforcement reports, registrar change logs, tabletop minutes.

Communication templates

• Leadership brief: Situational summary, current exposure, top three mitigations, and escalation contacts.
• Employees: Phishing indicators, reporting channel, MFA reminder, travel/offsite access guidance.
• Vendors: Require MFA, change control, and 24/7 contact path; confirm no hardcoded accounts; validate remote access approvals for OT.
• Regulators/partners: Pre-drafted notice format with incident classification and timeline.

Architecture view

        Internet → WAF/VPN → IdP MFA → SWG/Proxy → Apps
                    |                |
                 Registrar locks   DNSSEC
                    |                |
                OT DMZ → Jump host → OT network (segmented)
            

Retention and follow-through

Store tabletop notes, SIEM queries, restore evidence, registrar confirmations, MFA enforcement screenshots, and communications. Schedule quarterly destructive-malware drills, DNS-change monitoring reviews, and annual OT remote-access audits to demonstrate sustained vigilance.

Logging prerequisites

• Identity: Unified audit for IdP, VPN, OWA, and privileged access tools with 30–90 day retention.
• DNS: Centralized logging from authoritative and resolver layers; enable query/response logging.
• EDR: Ensure tamper protection and kernel sensors deployed on domain controllers and jump hosts.
• OT: Flow and packet logging in DMZ; asset inventory with firmware versions.

Tabletop injects (sample)

Governance cadence

Hold weekly threat posture reviews during heightened alert, then return to monthly cadence. Track action items, SLA performance for MFA/backup testing, and remediation of findings from each hunt or tabletop.

Supply-chain and remote access safeguards

• Reverify vendor access lists; disable dormant accounts; require MFA and time-bound approvals for all third-party sessions.
• Enforce signed updates for OT and IT software; validate hashes before installation; monitor for unauthorized tooling.
• Confirm out-of-band management interfaces are restricted (no public IPs) and monitored.

Runbook timeline (hours)

Post-incident assurance

After containment, capture lessons learned, update detection content, rotate credentials involved, and schedule follow-up hunts for 30 days. Verify integrity of logging pipelines to ensure IOCs were captured.

Leadership FAQ

• What is different now? Heightened likelihood of Iranian-attributed activity targeting remote access and DNS; destructive malware possible.
• How exposed are we? Summarize internet-facing assets, MFA coverage, registrar protections, and OT segmentation status.
• What are we doing? MFA enforcement, registrar locks, backup validation, hunts, tabletop, and vendor access tightening.
• What support is needed? Emergency change approvals, communication amplification, and accelerated procurement for missing controls.

Training snippets

Send a concise awareness note with screenshots of suspicious login prompts, DNS warning signs (certificate/name mismatches), and instructions to report unusual file deletion or device behavior immediately to the SOC.

Third-party coordination

Share vetted IOCs and required controls with critical suppliers and managed service providers; request confirmation of registrar locks, MFA coverage, and backup validation. Include escalation paths for coordinated response if shared infrastructure is targeted.

Align with sector ISAC sharing protocols to submit anonymized indicators and receive peer updates during the heightened threat period.

Ensure crisis management teams have up-to-date contact rosters with backups for weekends and holidays; confirm executive spokespersons are prepared with approved messaging if service disruption occurs.

Have legal counsel pre-review notification templates to expedite outreach if customer-impacting disruption occurs, aligning with contractual commitments and regulatory timelines.